Privacy policy
Last updated: 2026-10-01
Knuckleflow is built so that this page can be short. The app has no account, no server of its own holding your work, and no advertising or analytics code in it.
What the app collects
Nothing is collected about you. There is no sign-up, no profile, and no identifier tied to you as a person.
What stays on your device
Everything you create lives in Knuckleflow's own storage on your iPhone and is included in your device backup if you make one:
| What | Where it lives | How to remove it |
|---|---|---|
| Your status for each move | On your device | Settings → Reset progress, or delete the app |
| Saved combos | On your device | Delete the combo, Reset progress, or delete the app |
| Practice sessions and streak | On your device | Settings → Reset progress, or delete the app |
| App version and bundle identifier, at launch | Sent to stakflow.info to check for a critical update | Nothing is stored; see Update check below |
| Preferences (haptics, sound, click tone) | On your device | Settings → Reset progress, or delete the app |
Notifications
Knuckleflow can send you a reminder on days you have not practised, and a note when new moves are added to the library. That is everything it will ever send. Notifications are optional: the app explains what they are for before iOS asks you, and declining changes nothing else about the app. You can turn them off at any time in iOS Settings, or in Settings inside the app.
Push notifications are delivered by OneSignal, a third-party service, and its software is embedded in the app. If you turn notifications on, OneSignal is given a push subscription identifier and basic device information — the device model, operating system version, language, timezone and app version — so that a notification can reach this device. That identifier is not your name, your email or your Apple Account, and it is not linked to any of them.
If you never turn notifications on, no push subscription is created and nothing is sent. The software is present in the app either way; it becomes active only when you allow notifications.
Deleting the app removes the subscription. Writing to hello@stakflow.info also gets it deleted on request.
Update check
Each time Knuckleflow starts, it asks api.stakflow.info whether this version is still fit to use. It exists so that a build shipped with a serious fault can be replaced rather than left in your hands, and so that you are told about it rather than left wondering.
The request carries three things: the app's version, its bundle identifier, and — only if you have turned notifications on — the push subscription identifier. It carries no name, no email, no Apple Account and nothing you have done in the app. Nothing about you is written down at the other end; the answer is one of three words, and that is the end of it.
If the request fails for any reason — no network, a server fault, an answer the app cannot read — the app simply opens. It never keeps you out because it could not reach us.
What the app does not do
- No analytics or usage measurement of any kind.
- No advertising, no advertising identifier, no tracking across apps or websites.
- No location, camera, microphone, photo, contact or health access.
- Notifications are the only permission the app ever asks for, and only when you choose to see the request.
- OneSignal is the only third-party software in the app. There is no analytics or advertising SDK of any kind.
Payments
There are none. Knuckleflow is free and complete: no subscription, no in-app purchase and no advertising. The app contains no payment code, so there is no transaction for this policy to describe.
Children
Knuckleflow is rated for ages 4 and up. Beyond the launch check described above it collects nothing from anyone unless notifications are turned on, and that includes children; and contains no gambling, no simulated gambling, no chat and no user-to-user content. The cards drawn in the app carry no suits or values.
International transfers
If you turn notifications on, the push subscription is held by OneSignal on servers that may be outside your country. Apart from the push subscription and the launch check above, nothing the app holds leaves your device. If you email support, that message travels through your email provider and ours.
Your rights
You control the only copy of your data. Removing it is immediate and entirely in your hands: use Reset progress in Settings, or delete the app. There is no copy of it for us to hold, export or delete on your behalf. If you want to ask about any of this, write to hello@stakflow.info.
Support email
If you contact support, we keep your message and address only for as long as it takes to answer you, and we do not add you to any mailing list.
Changes to this policy
If the app ever starts doing something this page does not describe, this page changes first and the date at the top moves with it. Material changes will also be noted in the app's release notes.